U.S. patent application number 10/949940 was filed with the patent office on 2005-05-26 for high-frequency diode.
This patent application is currently assigned to Infineon Technologies AG. Invention is credited to Losehand, Reinhard.
Application Number | 20050110046 10/949940 |
Document ID | / |
Family ID | 34584716 |
Filed Date | 2005-05-26 |
United States Patent
Application |
20050110046 |
Kind Code |
A1 |
Losehand, Reinhard |
May 26, 2005 |
High-frequency diode
Abstract
A high-frequency diode has a first semiconductor area with a
first conductivity type as well as a barrier area adjacent to the
first semiconductor area, which has a second conductivity type,
which differs from the first conductivity type. Further, the
high-frequency diode has a second semiconductor area adjacent to
the barrier area, which has the second conductivity type and a
dopant concentration which is lower than the dopant concentration
of the barrier are or equal to zero. Further, the high-frequency
diode has a third semiconductor area adjacent to the second
semiconductor area, which has the same conductivity type and a
higher dopant concentration than the barrier area. Through such a
structure it is possible to provide a high-frequency diode with
short switching times and low bias.
Inventors: |
Losehand, Reinhard;
(Munchen, DE) |
Correspondence
Address: |
Maginot, Moore & Beck
Bank One Tower
111 Monument Circle, Suite 3000
Indianapolis
IN
46204
US
|
Assignee: |
Infineon Technologies AG
Munchen
DE
|
Family ID: |
34584716 |
Appl. No.: |
10/949940 |
Filed: |
September 24, 2004 |
Current U.S.
Class: |
257/199 ;
257/E29.336 |
Current CPC
Class: |
H01L 29/868
20130101 |
Class at
Publication: |
257/199 |
International
Class: |
H01L 023/52 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 25, 2003 |
DE |
103 44 609.5 |
Claims
1-20. (canceled)
21. A high-frequency diode, comprising: a first semiconductor area
having a first conductivity type; a barrier area adjacent to the
first semiconductor area having a second conductivity type, the
second conductivity type different than the first conductivity
type; a second semiconductor area adjacent to the barrier area, the
second semiconductor area having the second conductivity type and a
dopant concentration of between zero and a first limit, the first
limit being lower than a dopant concentration of the barrier area;
and a third semiconductor area adjacent to the second semiconductor
area, the third semiconductor area having a second conductivity
type and a higher dopant concentration than the barrier area.
22. The high-frequency diode according to claim 21, wherein the
first conductivity type comprises an n-conductivity type and the
second conductivity type comprises a p-conductivity type.
23. The high-frequency diode according to claim 21, wherein the
barrier area has a dopant concentration between 10.sup.15 and
10.sup.18 dopant atoms per cm.sup.3.
24. The high-frequency diode according to claim 23, wherein the
barrier area has a dopant concentration between 10.sup.16 and
10.sup.17 dopant atoms per cm.sup.3.
25. The high-frequency diode according to claim 21, wherein the
first limit comprises 10.sup.14.
26. The high-frequency diode according to claim 21, wherein the
first semiconductor area has a dopant concentration of greater than
10.sup.19 dopant atoms per cm.sup.3 and the dopant concentration of
the third semiconductor area is higher than 10.sup.19 dopant atoms
per cm.sup.3.
27. The high-frequency diode according to claim 21, wherein the
barrier area has a thickness within a value range between 0.2 .mu.m
and 0.8 .mu.m.
28. The high-frequency diode according to claim 27, wherein the
thickness of the barrier area is between 0.4 .mu.m and 0.6
.mu.m.
29. The high-frequency diode according to claim 21, wherein the
second semiconductor area has a thickness within a value range
between 4 .mu.m and 10 .mu.m.
30. The high-frequency diode according to claim 29, wherein the
thickness of the second semiconductor area is between 5 .mu.m and 8
.mu.m.
31. The high-frequency diode according to claim 21, wherein the
barrier area, the second semiconductor area and the third
semiconductor area have a lateral extension having a width, the
width being within a value range between 20 .mu.m and 100
.mu.m.
32. The high-frequency diode according to claim 31, wherein the
lateral extension width is within a value range between 40 .mu.m
and 60 .mu.m.
33. The high-frequency diode according to claim 31, wherein a
boundary structure is disposed adjacent a side of the barrier area,
a side of the second semiconductor area and a side of the third
semiconductor area, the boundary structure defining the lateral
extension of the barrier area, the second semiconductor area and
the third semiconductor area.
34. The high-frequency diode according to claim 33, wherein the
boundary structure comprises an isolating material.
35. The high-frequency diode according to claim 34, wherein the
first semiconductor area is configured to be electrically
conductively contacted by a contact point of a contacting
structure, wherein the contact point is disposed over the first
semiconductor area at a level that is higher than an interface
between the second semiconductor area and the third semiconductor
area.
36. The high-frequency diode according to claim 35, wherein the
contacting structure comprises at least one sub-structure of an
isolating material.
37. The high-frequency diode according to claim 21, wherein the
first semiconductor area is disposed on a substrate, the substrate
comprising a semi-isolating material.
38. A high-frequency circuit comprising: a switch having a
high-frequency diode, the high frequency diode comprising a cathode
including a first semiconductor area having a first conductivity
type, a barrier area adjacent to the first semiconductor area
having a second conductivity type, the second conductivity type
different than the first conductivity type, a second semiconductor
area adjacent to the barrier area, the second semiconductor area
having the second conductivity type and a dopant concentration of
between zero and a first limit, the first limit being lower than a
dopant concentration of the barrier area and an anode including a
third semiconductor area adjacent to the second semiconductor area,
the third semiconductor area having a second conductivity type and
a higher dopant concentration than the barrier area; and a
controller configured to controllably close and open the switch
depending on a control signal, wherein the controller is further
configured to apply a positive bias between the cathode and the
anode of the high-frequency diode when opening the switch.
39. The high-frequency circuit according to claim 38, wherein a
switch input is configured to be coupled to an output voltage of a
high-frequency source, the high-frequency source operable to
generate a voltage signal having a high-frequency voltage
amplitude, and wherein the positive bias is smaller or equal to
half the high-frequency voltage amplitude.
40. The high-frequency switch according to claim 39, wherein the
positive bias is less than or equal to a third of the
high-frequency voltage amplitude.
Description
BACKGROUND OF THE INVENTION
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from German Patent
Application No. 10344609.5, which was filed on Sep. 25, 2003 and is
incorporated herein by reference in its entirety.
[0002] 1. Field of the Invention
[0003] The present invention refers generally to a high-frequency
diode and particularly to a high-frequency diode requiring a lower
bias in the blocking state than high-frequency diodes according to
the prior art.
[0004] 2. Description of the Related Art
[0005] Silicon high-frequency switches are often realized with PIN
diodes. This results from the structure of the PIN diodes favorable
for high-frequency technical applications, as it is, for example,
shown in FIG. 3. Thereby, the PIN diode comprises a half-isolating
substrate 300, into which a well 302 is embedded, which has an
n-doped semiconductor material with a high n.sup.+ dopant
concentration compared to the half-isolating substrate 300 (buried
layer n-cathode). Further, a second semiconductor area is disposed
in a central area 304 of a surface 306 of the well 302, which
comprises an n-doped semiconductor material with a lower dopant
concentration than the semi-isolating substrate 300 (n.sup.-
intrinsic zone, I-zone). Further, a third semiconductor area 312 is
disposed on a surface 310 of the second semiconductor area 308,
which comprises a p-doped semiconductor material with a high
p.sup.+-doped concentration (p-anode). The third semiconductor area
312 and the second semiconductor area 308 are bounded on the sides
by a boundary structure 314, wherein the boundary structure 314
further estends into the first semiconductor area 302. The boundary
structure 314 is formed by an oxide filled isolation trench (oxide
filled trench). A filling material 316 is disposed on the side of
the boundary structure 314 opposing the second semiconductor area
308 and the third semiconductor area 312, which has a recess 320 in
the marginal area 318. Further, a contacting structure 322 is
disposed in the recess 320, which comprises sub-areas 324 of
electrically conductive material and sub-areas 326 of electrically
isolating material. The electrically conductive sub-areas 324 are
further electrically conductively connected to the first
semiconductor area 302, so that the first semiconductor area 302
can be contacted electrically conductively from a contact point 328
via the contacting structure 322. Further, a cover layer 330 is
disposed at least partly on the boundary structure 314 as well as
the filling material 316.
[0006] The favorable characteristics by which a PIN diode is
optimally suited as a high-frequency switch, are particularly given
by the weakly n-doped second semiconductor area 308, which is
disposed between the highly n-doped first semiconductor area 302
and the highly p-doped third semiconductor area 312. When applying
a blocking voltage, a space charge region forms between a
pn-junction, wherein the space charge region has a space charge
region width in the respectively differently doped semiconductor
areas which depends on the dopant concentration in the respective
semiconductor area. Since, when applying a blocking voltage between
the first semiconductor area 302 and the third semiconductor area
312 between the first semiconductor area 302 and the second
semiconductor area 308, a space charge region results which has a
large width in the second semiconductor area 308 due to the low
charge carrier density, the PIN diode illustrated in FIG. 3 thus
forms a low blocking capacity due to the broad space charge region
between the first semiconductor area 302 and the second
semiconductor area 308, whereby the favorable blocking
characteristics of the PIN diodes as high-frequency switch are
effected.
[0007] WLAN systems require an antenna switch, which can be used
for two frequency bands at 2.5 and 5.5 GHz, has short switching
times of 80 ns and copes with powers of up to 1 W. The PIN diode
illustrated in FIG. 3 is suitable both for realizing integrated
circuits and discrete flip-chip diodes. Classical diode structures
with wire bonding and backside contact are not suitable any more
for the high frequencies. Thus, a buried-layer cathode 302 with
trench sinker in the shape of the illustrated contacting structure
322 is used, which leads the cathode contact towards the top.
Further, the diode is surrounded by a trench in the form of the
boundary structure 314, which keeps the injection volume small and
thus the switching time short. To keep the injection volume small
and thus the switching times short, a PIN diode according to FIG. 3
has additionally a thickness 332 of merely 7 .mu.m and a width 334
of merely 50 .mu.m. Further, the contacting structure 322 has also
sub-areas of an isolating material, whereby the volume of the
conductive material 326 can be reduced and thus the shortening of
the switching time of the PIN diode is possible by reducing the
number of charge carriers (for example electrons) to be moved.
[0008] The diode does fulfill the above requirement, however, it is
disadvantageous that it requires a high bias voltage of almost the
value of the high-frequency amplitude, which is 10 V at 1 Watt,
during blocking operation with 1 W power level. In other words, for
blocking the current flow, the PIN diode requires a bias which
corresponds to approximately the height of the high-frequency
amplitude which is to be blocked. Apart from a time voltage curve
410 and a time current curve 412, the oscillogram in the lower
sub-image of FIG. 4 shows also a DC voltage level of 8 V, an
amplitude of the fundamental wave of 10 V and level distances of
64, 68 and 74 dB for the H2, H3 and H4 harmonics. A simulation of
the blocking behavior (see FIG. 4, lower sub-image) shows that with
8 V bias the forward current is suppressed so far that a
sufficiently large harmonic distance of 60 dB is kept.
[0009] The left upper sub-image of FIG. 4 shows a doping profile,
which represents a hole concentration 420 of the p-anode at the
left margin as well as an electron concentration 422 of the
n-cathode (buried layer n-cathode) at the right margin. Further,
the doping profile shows that charge carriers, i.e. electrons
and/or holes, already enter the second semiconductor area (I-zone),
wherein the second semiconductor area is represented in the central
area of the doping profile. The current flowing thereby is too
small to cause a mentionable isolation deterioration and to affect
the harmonic behavior. In the right upper sub-image, the potential
curve in the third, second and first semiconductor area as well as
in the barrier area is illustrated at different operating
times.
[0010] One possible process for reducing the required bias is to
make the I-zone of the PIN diode long and thus to reduce the
turn-on speed of the PIN diode so far that a time period of a
positive half-wave of a high-frequency modulation is not sufficient
for the PIN diode to turn on. In other words, the thickness 332 of
the second semiconductor area 308 illustrated in FIG. 3 is enlarged
such that the charge carriers cannot drift through the second
semiconductor area 308 during the positive half-wave of the
high-frequency modulation and thus switching through of the PIN
diode is prevented. Thus, the thickness 332 of the second
semiconductor area 308 is dependent on the operating frequency of
the PIN diode. However, it is one disadvantage of this method that
the switching time of the PIN diode switch will become longer.
SUMMARY OF THE INVENTION
[0011] It is the object of the present invention to provide a
high-frequency switch with low switching times, a low bias as well
as a switching possibility for high powers.
[0012] In accordance with a first aspect, the present invention
provides a high-frequency diode, having a first semiconductor area
having a first conductivity type; a barrier area adjacent to the
first semiconductor area having a second conductivity type, which
differs from the first conductivity type; a second semiconductor
area adjacent to the barrier area, which has the second
conductivity type and a dopant concentration, which is lower than a
dopant concentration of the barrier area of equal to zero; and a
third semiconductor area adjacent to the second semiconductor area,
which has a second conductivity type and a higher dopant
concentration than the barrier area.
[0013] In accordance with a second aspect, the present invention
provides a high-frequency circuit, having a switch with a
high-frequency diode according to claim 1, wherein the
high-frequency diode comprises an anode and a cathode; a control
means, which is formed to close or open the switch depending on a
control signal, wherein the control means is further formed to
apply a positive bias between the cathode and the anode of the
high-frequency diode when opening the switch.
[0014] The present invention is based on the knowledge that by
inserting a barrier area between the first semiconductor area and
the second semiconductor area of the high-frequency diode, a short
time flowing of electrons during switching from blocking polarity
to flow polarity can be prevented. A reason therefore is that a
space charge region is formed during blocking polarity of the
diode, which remains for several ns when switching from blocking
polarity to flow polarity of the diode. The potential building up
in the space charge region thus forms an effective potential
barrier against electron emission for a short time interval after
switching the high-frequency diode from blocking polarity to flow
polarity. Thereby, the turn-on procedure is not avoided but
delayed.
[0015] The inventive solution provides the advantage that by
forming the barrier area between the first semiconductor area and
the second semiconductor area, a reduction of the bias can also be
obtained with lower thicknesses of the second semiconductor area
(i.e. with shorter I-zone widths). Thus, the switching time of the
high-frequency diode switch can be kept short. Further, reduction
of the switching behavior with regard to the high-frequency powers
to be switched is not to be expected.
[0016] According to a preferred embodiment of the present
invention, the material with the first conductivity type comprises
an n-doped semiconductor material, and the material with the second
conductivity type a p-doped semiconductor material.
[0017] Preferably, the barrier area has a dopant concentration
between 10.sup.15 and 10.sup.18 dopant atoms per cm.sup.3.
[0018] According to a further preferred embodiment of the present
invention, the barrier area has a dopant concentration between
10.sup.16 and 10.sup.17 dopant atoms per cm.sup.3.
[0019] According to a further aspect of the present invention, the
dopant concentration of the second semiconductor area is smaller
than 10.sup.14 dopant atoms per cm.sup.3 or equal to 0.
[0020] Preferably, the first and third semiconductor area of the
high-frequency diode has a dopant concentration, which is larger
than 10.sup.19 dopant atoms per cm.sup.3.
[0021] According to a further preferred embodiment of the present
invention, the barrier area comprises a thickness between the first
semiconductor area and the second semiconductor area, which lies
within a value range between 0.2 .mu.m and 0.8 .mu.m.
[0022] According to a further preferred embodiment of the present
invention, the thickness of the barrier area lies in a range within
0.4 .mu.m and 0.6 .mu.m.
[0023] According to a further preferred embodiment of the present
invention, the second semiconductor area has a thickness between
the barrier area and the third semiconductor area, which lies
between a value range between 4 .mu.m and 10 .mu.m.
[0024] Preferably, the thickness of the second semiconductor area
lies in a value range between 5 .mu.m and 8 .mu.m.
[0025] According to a further aspect of the present invention, the
barrier area, the second semiconductor area and the third
semiconductor area have a lateral extension, which lies within a
value range between 20 .mu.m and 100 .mu.m.
[0026] Preferably, the lateral extension lies within a value range
between 40 .mu.m and 60 .mu.m.
[0027] According to a further preferred embodiment of the present
invention, a boundary structure is disposed on the side of the
barrier area, the second semiconductor area and the third
semiconductor area, which defines the lateral extension of the
barrier area, the second semiconductor area and the third
semiconductor area.
[0028] Preferably, the boundary structure comprises an isolating
material.
[0029] According to a further aspect of the present invention, the
first semiconductor area can be electrically conductively contacted
by a contact point of a contacting structure, wherein the contact
point is disposed higher over the first semiconductor area than an
interface between the second and the third semiconductor area.
[0030] Preferably, the contacting structure comprises at least one
sub-structure of an isolating material.
[0031] According to a further preferred embodiment of the present
invention, the first semiconductor area is disposed on a substrate,
which comprises a semi-isolating material.
[0032] According to a further aspect of the present invention, the
inventive high-frequency diode is part of a switch of a
high-frequency circuit, wherein the high-frequency diode has an
anode and a cathode, wherein the high-frequency circuit has a
control means, which is formed to close or to open the switch
depending on a control signal, wherein the control means is further
formed to apply a positive bias between the cathode and the anode
of the high-frequency diode when opening the switch.
[0033] According to a further preferred embodiment of the present
invention, a switch input of the switch can be coupled to an output
voltage of a high-frequency source, wherein a voltage signal can be
supplied from the high-frequency source, which has a high-frequency
voltage amplitude and wherein the positive bias is smaller or equal
to half the high-frequency voltage amplitude.
[0034] According to a further preferred embodiment, the positive
bias is smaller or equal to one third of the high-frequency voltage
amplitude.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] These and other objects and features of the present
invention will become clear from the following description taken in
conjunction with the accompanying drawings, in which:
[0036] FIG. 1 is a preferred embodiment of an inventive
high-frequency diode in a cross-sectional view;
[0037] FIG. 2 is a representation of several simulation diagrams of
the inventive high-frequency diode;
[0038] FIG. 3 is a cross-sectional view of a high-frequency diode
according to the prior art; and
[0039] FIG. 4 is a representation of several simulation diagrams of
the conventional high-frequency diode.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0040] In the following description of the preferred embodiment of
the present invention, the same reference numbers are used for the
similar elements illustrated in the different figures.
[0041] FIG. 1 shows a preferred embodiment of the inventive
high-frequency diode, which is structured similar to the
conventional high-frequency diode illustrated in FIG. 3. Contrary
to the high-frequency diode illustrated in FIG. 3, the inventive
high-frequency diode has a barrier area 100, which is disposed in
the central area 304 on the surface 306 of the first semiconductor
area 302. Further, the second semiconductor area 308 is disposed on
a surface 102 of the barrier area. Thereby, the structure
illustrated in FIG. 1 results, where the barrier area 100 is
disposed between the first semiconductor area 302 and the second
semiconductor area 308. The barrier area 100 (the injection
barrier) consists preferably of a p-doped semiconductor zone with
an acceptor concentration of about 10.sup.16 dopant atoms per
cm.sup.3, wherein the barrier area 100 has a thickness 104 of about
0.5 .mu.m. The barrier area 100 (the electron emission barrier) is
thus built up by a weakly p-doped layer adjacent to the highly
n-doped cathode area of the first semiconductor area 302 of the
inventive high-frequency diode. The p.sup.+In.sup.+ dopant profile
of a conventional PIN diode is thus replaced by a
p.sup.+Ip.sup.-n.sup.+ dopant profile of the inventive
high-frequency diode. Thereby it is prevented that electrons can
reach the second semiconductor area 308 (I area) of the inventive
high-frequency diode shortly after switching from the blocking
polarity to the flow polarity, i.e. in the initial flow phase.
Holes, however, can enter the second semiconductor area 308 but
lead only to low currents due to the low hole movability.
[0042] In the preferred embodiment of the present invention, the
thickness 332 of the second semiconductor area 308 is 6.5 .mu.m.
Depending on the intended field of application of the inventive
high-frequency diode as high-frequency switch, the thickness 332 of
the second semiconductor area 308 can lie in a value range of, for
example, 4 .mu.m and 10 .mu.m. For a field of application of the
inventive high-frequency diode in the frequency bands of 2.5 and
5.5 GHz, the value range of the thickness 332 of the second
semiconductor area 308 is preferably chosen between 5 .mu.m and 8
.mu.m. For an optimum adaptation of the injection volume, further,
the width 334 of the barrier area 100, the second semiconductor
area 308 as well as the third semiconductor area 312 can be chosen
within a value range of 20 .mu.m to 100 .mu.m. For the named field
of application in the two frequency bands, preferably, a width 334,
i.e. a lateral extension of the barrier area 100, the second
semiconductor area 308 as well as the third semiconductor area 312
is preferably chosen within a value range of 40 .mu.m to 60
.mu.m.
[0043] It should be noted that the i area of the PIN diode can be
weakly n-doped or weakly p-doped. Thus, the doping type is
arbitrary, as long as this area has a high impedance. Here, the i
area can have the same type as the substrate. Since weakly p-doped
isolating substrates are more favorable than n-doped substrates
with regard to isolation properties, p-substrates are preferred for
the invention, although leaking currents due to a too weak
isolation are unproblematic, particularly for high-frequency
diodes.
[0044] FIG. 2 shows several simulation diagrams, which represent
the behavior of the inventive high-frequency diode according to the
preferred embodiment. In the lower sub-image, the voltage curve 200
and the current curve 202, which result when providing the
inventive high-frequency diode with a high-frequency signal, are
plotted across time. Further, it can be seen from the lower
sub-image of FIG. 2 that the bias can be lowered to a common VCC
level of 2.8 V. Again, the amplitude of the high-frequency signal
is approximately 10 V. The harmonics levels are also far enough
away in this case: from 63, 84 and 87 dB for the H2, H3 and H4
harmonics. Again, the left upper sub-image of FIG. 2 shows the
doping profile with an electron concentration 210 and a hole
concentration 212, plotted across the extension of the second
semiconductor area and the barrier area, which are illustrated on
the abscissa starting from the left margin of the diagram. It can
be seen from the doping profile that the hole concentration 212
extends into the second semiconductor area, which is disposed on
the abscissa mainly between the range of 1 .mu.m to 7.5 .mu.m,
starting from the third semiconductor area illustrated at the left
margin of the image. Compared with this, it can be seen from the
left upper sub-image in FIG. 2 that the electron concentration 210
first falls heavily starting from the first semiconductor area
illustrated at the right margin of the diagram in the direction
towards the second semiconductor area (area 214), which can be
explained by the p-doping of the barrier area. Further, in the
second semiconductor area, which is disposed between the abscissa
values of 1 .mu.m to 7.5 .mu.m, the electron concentration 210
assumes a concentration, which lies below the hole concentration
212.
[0045] Thereby it can be seen that in the inventive high-frequency
diode the injection of electrons from the first semiconductor area
to the second semiconductor area is made more difficult and is
briefly prevented, respectively, by inserting the barrier area.
[0046] The exact potential curve is illustrated in FIG. 2 at the
top right for the different phases of the high-frequency signal.
Thereby, again on the abscissa, the extension of the second
semiconductor area as well as the barrier area is illustrated
starting from the third semiconductor area illustrated at the left
margin of the diagram, while the voltage with regard to a potential
of the third semiconductor area is plotted on the ordinate.
Compared to the right upper sub-image in FIG. 4, which represents
the potential curve of a conventional high-frequency diode, it can
now be seen that at some times a significantly higher potential
(see potential curves 220) can be observed in the inventive
high-frequency diode compared to the conventional high-frequency
diode. This results from the fact that the space charge region
formed during blocking polarity in the diode remains for several
nanoseconds at a transition to the flow polarity. During these
nanoseconds, wherein the space charge region still exists, a reload
procedure takes place, with an effect like a voltage opposing the
flow polarity, whereby the effective potential barrier against an
electron emission from the first semiconductor area to the second
semiconductor area results. This opposing voltage can thus be seen
in the potential diagram in the right upper sub-image of FIG. 2 by
the potential curves 220.
[0047] It should further be noted that the described facts are
simulation results.
[0048] Although a preferred embodiment of the present invention has
been discussed in detail above, it is obvious that the present
invention is not limited to this embodiment.
[0049] While this invention has been described in terms of several
preferred embodiments, there are alterations, permutations, and
equivalents which fall within the scope of this invention. It
should also be noted that there are many alternative ways of
implementing the methods and compositions of the present invention.
It is therefore intended that the following appended claims be
interpreted as including all such alterations, permutations, and
equivalents as fall within the true spirit and scope of the present
invention.
[0050] Reference Number List
[0051] 100 barrier area
[0052] 102 surface of the barrier area
[0053] 104 thickness of the barrier area
[0054] 200 voltage curve in the inventive high-frequency diode
[0055] 202 current curve in the inventive high-frequency diode
[0056] 210 electron concentration in the inventive high-frequency
diode
[0057] 212 hole concentration in the inventive high-frequency
diode
[0058] 214 charge carrier concentration in the barrier area 100
[0059] 220 potential curves caused by the space charge region in
the high-frequency diode
[0060] 300 substrate
[0061] 302 first semiconductor area
[0062] 304 central area of the first semiconductor area
[0063] 306 surface of the first semiconductor area
[0064] 308 second semiconductor area
[0065] 310 surface of the second semiconductor area
[0066] 312 third semiconductor area
[0067] 314 boundary structure
[0068] 316 filling material
[0069] 318 margin area
[0070] 320 recess in the margin area 318
[0071] 322 contacting structure
[0072] 324 conductive sub-area of the contacting structure 322
[0073] 326 isolating sub-area of the contacting structure 322
[0074] 328 contact point
[0075] 330 cover layer
[0076] 332 thickness of the second semiconductor area 308
[0077] 334 lateral extension and width, respectively, of the
barrier area 100, the second semiconductor area 308 and the third
semiconductor area 312
[0078] 410 voltage curve in the conventional high-frequency
diode
[0079] 412 current curve in the conventional high-frequency
diode
[0080] 420 hole concentration in the conventional high-frequency
diode
[0081] 422 electron concentration in the conventional
high-frequency diode
* * * * *